Measuring method of nondestructive heat spray-on lining thickness

The non-destructive measurement methods of thermal spray coating thickness mainly include the following. Different non-destructive measurement methods are suitable for different types of coatings and measurement requirements. When measuring the thickness of thermal spray coatings, the appropriate measurement method should be selected according to the specific coating materials and experimental requirements, and the relevant operating procedures and standards should be followed. In addition, when using non-destructive measurement methods, the accuracy of the instrument and the reliability of the measurement results should be ensured, and calibration and verification should be carried out if necessary.

X-ray Diffraction (XRD): The thickness of the coating can be determined by measuring the X-ray diffraction pattern of the thermally sprayed coating and analyzing the position and intensity of the diffraction peaks. This method is suitable for thickness measurement of metallic or ceramic coatings.

Ultrasonic Thickness Measurement: The thermal spray coating is scanned using an ultrasonic Detector, and the thickness of the coating is calculated by measuring the propagation time and reflected signal of ultrasonic waves. This method is suitable for thickness measurement of metal coatings and some ceramic coatings.

Laser scanning measurement method: Use a laser scanner or laser rangefinder to scan the surface of the coating, measure the distance between the laser and the coating, and calculate the thickness of the coating based on the scanning results. This method is suitable for thinner coatings and flat surfaces.

Magnetic induction method: Use a magnetic induction measuring instrument to measure the magnetic field strength or magnetic induction intensity of the coating surface, and deduce the thickness of the coating through a calibration curve or related algorithms. This method is suitable for thickness measurement of magnetic coatings.

Infrared thermal imaging method: The thermal distribution image of the coating surface is recorded by an infrared thermal imaging camera, and the thickness of the coating is inferred from the change of the thermal distribution. This method is suitable for coatings with thermal barrier effects, such as thermal barrier coatings.

Among them, the magnetic induction method is a commonly used non-destructive measurement method for measuring the thickness of magnetic coatings. The following are the general test steps and precautions for the magnetic induction method:

Test steps:

1. Prepare test instruments: magnetic induction measuring instrument, calibration sample, magnetic coating sample.

2. Calibration of magnetic induction measuring instruments: Calibration is performed using calibrated samples to determine the sensitivity and zero point of the instrument.

3. Prepare magnetic coating samples: Make sure the coating surface is flat, clean, and that the coating is magnetically sound.

4. Keep the magnetic inductIon Meter close to the coating surface at a suitable distance.

5. Start the magnetic induction measuring instrument, make measurements, and record the measurement results.

6. According to the calibration curve of the instrument or related algorithms, the thickness of the magnetic coating is deduced.

Precautions:

1. Preparation of the sample surface: The coating surface should be flat and clean without obvious irregularities or contamination to ensure the accuracy of the measurement results.

2. Calibration of the instrument: Before taking the measurement, make sure that the magnetic induction measuring instrument has been properly calibrated to ensure the accuracy of the measurement results.

3. Selection of measurement position: Select the appropriate measurement position, usually choose to perform multiple measurements in different areas of the coating to obtain a more accurate average value.

4. Measuring distance control: ensure that the distance between the magnetic induction measuring instrument and the coating surface is constant, avoid being too close or too far, and ensure the stability of the measurement results.

5. Repeatability and Accuracy: Take multiple measurements and calculate the average to improve the repeatability and accuracy of the measurement results.

6. Calibration curve and algorithm: According to the specific magnetic induction measuring instrument model and coating material, select the appropriate calibration curve or algorithm to calculate the measurement result.

7. Use of calibrated samples: Check and replace calibrated samples regularly to ensure the accuracy of measuring instruments.

8. Safety precautions: During operation, pay attention to the safe use of the instrument and personal safety protection.

Specific test procedures and precautions may vary depending on the magnetic inductIon Meter and coating material. Before testing, it is recommended to refer to the operating manual of the magnetic inductIon Meter and relevant standards and procedures to ensure correct operation and accurate measurement.